I have an AEON multi, used by the ST app “extreme temp monitor” to notify me on excessive temps in wine room.
But, I get bogus high temp notifications frequently - as often once a week or so. I know they are bogus since the temps reading claimed are sometimes >100degs. Sometimes the bogus high readings are believable (e.g. in the 70’s), but then the next temp reported will be back into the 50/60’s as expected. Frequency of these bogus alerts seems to have increased recently, so I no longer want to “ignore” them.

So I don’t really know where in the stack the error is introduced - a bad temp reading from the device or an error upstream in the “temp monitor” app (latter seems unlikely).

The AEON is USB-powered, so battery problems would not explain it.

Are messages from the sensor protected from transport errors? (Sorry, I’m not that familiar with ZWave protocols but have to believe there’s robust transport at the lower levels.)

I’m guessing this is happing at the transmission level. We’ve seen quite a bit of corrupt Z-Wave traffic, especially in large noisy networks. Newer Aeon and Fibaro sensors have sufficient protection against transmission errors, but the original Aeon Multisensor can have some errors. I think this usually happens when the sensor’s original repeater route is no longer working and it has to use ad-hoc routing. Here’s what I would try:

Run a Z-Wave repair and try again if there are errors (note that if you have a big z-wave network, like 40+ devices, this doesn’t seem to work well so you may have to skip this step)

Rejoin the sensor in its current location: Without excluding it first, go to + Connect New Device and press the button in the multisensor as if adding a new device. It won’t pop up in the app because it’s already in your SmartThings, but it will run the protocol-level inclusion stuff again. I think the red LED inside of the sensor should come on for a while.

If the problems persist and you’re getting repeated errors from network repair, you can try the rejoin procedure on repeaters that are erroring in repair.

We are planning a feature to better support rejoining devices to fix them and to walk you through these steps when devices are acting up.

Guess time has now told… after resetting the network/device things seemed better for awhile but in last three days I’ve received temp alerts of 85 and 582 degrees – so the sensor itself is crap. Since this was a prime use case for why I bought into ST in the first place I’ll have to replace it with a more robust temp sensor. Any recommendations for same would be appreciated.